more easy printable atom parts(x_end_a,x_moter,x_carriage_lm_abc_set)

base printer is genkei [atom](https://github.com/hironaokato/atom_rc)
It was easier to print than the original parts

modified by onShape
https://cad.onshape.com/documents/2c2a47a4874a451bbae52e10/w/72d3ecc78847416497e807bc/e/399b262bed5b4e5e9e49d0b8